Method of manufacturing semiconductor device and substrate processing apparatus

ABSTRACT

A film is formed on a substrate by performing a cycle at least twice, the cycle including a nucleus formation process for forming nuclei on the substrate and a nucleus growth suppression process for suppressing growth of the nuclei. A time required for the nucleus growth suppression process is less than or equal to a time required for the nucleus formation process. Alternatively, the nucleus formation process is further performed after the cycle is repeatedly performed a plurality of times.

CROSS-REFERENCE TO RELATED PATENT APPLICATION

This U.S. non-provisional patent application claims priority under 35U.S.C. §119 of Japanese Patent Application No. 2010-195662, filed onSep. 1, 2010, in the Japanese Patent Office, and International PatentApplication No. PCT/JP2011/069319, filed on Aug. 26, 2011, in the WIPO,the entire contents of which are hereby incorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a method of manufacturing asemiconductor device including a substrate processing process, and asubstrate processing apparatus, and more particularly, to a method ofmanufacturing a semiconductor device including forming a silicon filmand a substrate processing apparatus.

2. Description of the Related Art

In one process of a manufacturing process of a semiconductor device, aNAND flash memory developed after 2X-nm NAND flash memory has beensuggested to be applied to a terabit cell array transistor (TCAT) usingeither a floating gate (FG) structure including a silicon film or thesilicon film as a channel of a longitudinal transistor and to bit-costscalable (BICS) technology so as to prevent interference from occurringbetween adjacent cells and reduce bit costs.

However, when the silicon film is used in this case, the roughness (Rms)of the silicon film may be degraded, thereby preventing high carriermobility from being achieved. Also, when the silicon film is used as apart of a semiconductor device, the performance of the semiconductordevice may not be sufficiently exhibited, thereby lowering thethroughput.

On the other hand, Japanese Patent Application Laid-Open No. H7-249600discloses that after a silicon film is formed, a surface of the siliconfilm is polished using an abrasive to planarize the surface of thesilicon film.

SUMMARY OF THE INVENTION

However, pollutants or particles may be generated during polishing of asurface of a silicon film and may then be mixed with a substrateincluding the silicon film. In this case, the quality of the substrateor the performance of a semiconductor device may be degraded.

It is an object of the present invention to provide a method ofmanufacturing a semiconductor device, which is capable of preventing thequality of a substrate or the performance of the semiconductor devicefrom being degraded, and a substrate processing apparatus.

According to one aspect of the present invention, there is provided amethod of manufacturing a semiconductor device, the method includingforming a silicon film by performing a cycle at least twice, the cycleincluding a nucleus growth suppression process for supplying achlorine-containing gas onto a substrate to suppress a growth of nucleiand control a local growth of silicon on the substrate and a nucleusformation process for supplying a silicon-containing gas onto thesubstrate to form silicon nuclei on the substrate, wherein a timerequired for the nucleus growth suppression process is less than orequal to a time required for the nucleus formation process.

According to another aspect of the present invention, there is provideda substrate processing apparatus including a process chamber configuredto process a substrate; a chlorine-containing gas supply systemconfigured to supply at least a chlorine-containing gas into the processchamber; a silicon-containing gas supply system configured to supply atleast a silicon-containing gas into the process chamber; and acontroller configured to control at least the chlorine-containing gassupply system and the silicon-containing gas supply system to form asilicon film by performing a cycle at least twice including a nucleusgrowth suppression process for supplying the chlorine-containing gasonto the substrate to suppress a growth of nuclei and control a localgrowth of silicon on the substrate and a nucleus formation process forsupplying the silicon-containing gas onto the substrate to form siliconnuclei on the substrate, wherein a time required for the nucleus growthsuppression process is less than or equal to a time required for thenucleus formation process.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a semiconductor manufacturing apparatusaccording to a first embodiment of the present invention.

FIG. 2 shows a side cross-section of a structure of a processing furnaceand each part of the substrate manufacturing apparatus according to thefirst embodiment of the present invention.

FIG. 3 is a schematic view of the processing furnace and peripheralstructures of the substrate manufacturing apparatus according to thefirst embodiment of the present invention.

FIGS. 4A to 4D are schematic views illustrating a state of a substrateaccording to each process in the first embodiment of the presentinvention.

FIG. 5 is a graph showing a result of forming a silicon film accordingto the first embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First Embodiment

Hereinafter, the first embodiment of the present invention will bedescribed in detail with reference to the appended drawings. FIG. 1 is aperspective view of a semiconductor manufacturing apparatus 10 as asubstrate processing apparatus according to the first embodiment of thepresent invention. The semiconductor manufacturing apparatus 10 is abatch-type vertical heat treatment apparatus and includes a housing 12in which main parts are disposed. In the semiconductor manufacturingdevice 10, a Front Opening Unified Pod (FOUP) (hereinafter referred toas a pod) 16 which is a substrate receiver that receives a wafer 200 asa substrate formed of, for example, silicon (Si) or silicon carbide(SiC) is used as a wafer carrier. A pod stage 18 is disposed in front ofthe housing 12, and the pod 16 is conveyed to the pod stage 18. Forexample, 25 sheets of wafers 200 are received in the pod 16, and the pod16 is dosed with a cover and then placed on the pod stage 18.

In the housing 12, a pod conveying device 20 is disposed at a front sideof the housing 12 to face the pod stage 18. A pod shelf 22, a pod opener24, and a substrate number detector 26 are disposed near the podconveying device 20. The pod shelf 22 is disposed above the pod opener24 and configured to hold a plurality of pods 16 while placing theplurality of pods 16. The substrate number detector 26 is disposedadjacent to the pod opener 24. The pod conveying device 20 conveys thepod 16 among the pod stage 18, the pod shelf 22, and the pod opener 24.The pod opener 24 opens the cover of the pod 16, and the substratenumber detector 26 detects the number of the wafers 200 in the pod 16,the cover of which is open.

In the housing 12, a substrate transfer machine 28 and a boat 217 whichis a substrate holder are disposed. The substrate transfer machine 28may include an arm (tweezers) 32, and is configured to be verticallyrotated by a driving unit (not shown). The arm 32 may be used to takeout, for example, five sheets of wafers 200. By moving the arm 32, thewafers 200 are transferred between the pod 16 disposed on a location ofthe pod opener 24 and the boat 217.

FIG. 2 is a schematic longitudinal cross-sectional view of a structureof a processing furnace 202 of a substrate processing apparatusaccording to an embodiment of the present invention.

As illustrated in FIG. 2, the processing furnace 202 includes a heater206 as a heating device. The heater 206 has a tube shape, e.g., acylindrical shape, and is vertically installed and supported by a heaterbase (not shown) which is a holding plate.

In the heater 206, a process tube 203 as a reaction tube having aconcentric shape with the heater 206 is provided. The process tube 203includes an inner tube 204 which is an internal reaction tube, and anouter tube 205 which is an external reaction tube installed at an outerside thereof. The inner tube 204 is formed of a heat-resistive material,e.g., quartz (SiO₂) or silicon carbide (SiC), and has a cylindricalshape having open upper and lower portions. A process chamber 201 isformed in a hollow portion of the inner tube 204. The process chamber201 is configured to receive the wafers 200 as substrates, in a state inwhich the wafers 200 are arranged in a vertically multi-layeredstructure in a horizontal posture using the boat 217 which will bedescribed in detail below. The outer tube 205 is formed of aheat-resistive material, e.g., quartz (SiO₂) or silicon carbide (SiC).The outer tube 205 has an internal diameter that is greater than anexternal diameter of the inner tube 204, has a cylindrical shape, anupper end of which is closed and a lower end of which is open, and has aconcentric shape with the inner tube 204.

A manifold 209 is provided below the outer tube 205 to have a concentricshape with the outer tube 205. The manifold 209 is formed of, forexample, stainless steel, and has a cylindrical shape, upper and lowerends of which are open. The manifold 209 is engaged with the inner tube204 and the outer tube 205 to support the inner tube 204 and the outertube 205. An O-ring 220 a is installed as a sealing member between themanifold 209 and the outer tube 205. Since the manifold 209 is supportedby the heater base (not shown), the process tube 203 is verticallymaintained. A reaction container is formed mainly by the process tube203 and the manifold 209.

In the manifold 209, nozzles 230 a, 230 b, and 230 c which are gasinjection ports are installed to communicate with the inside of theprocess chamber 201. Gas supply pipes 232 a, 232 b, and 232 c areconnected to the nozzles 230 a, 230 b, and 230 c, respectively. Asilicon-containing gas source 300 a, a chlorine-containing gas source300 b, and an inert gas source 300 c are connected to upstream sides ofthe gas supply pipes 232 a, 232 b, and 232 c which are opposite to sidesof the gas supply pipes 232 a, 232 b, and 232 c connected to the nozzles230 a, 230 b, and 230 c via mass flow controllers (MFCs) 241 a, 241 b,and 241 c which are gas flow rate controllers and valves 310 a, 310 b,and 310 c which are switching devices. A gas flow rate control unit 235is electrically connected to the MFCs 241 a, 241 b, and 241 c so as tocontrol a flow rate of gas to be supplied in a desired level at adesired timing.

The nozzle 230 a that supplies a silicon-containing gas, e.g., disilanegas (Si₂H₆), is formed of, for example, a quartz material and isinstalled in the manifold 209 to pass through the manifold 209. At leastone nozzle 230 a is located below rather than the range which isopposite the heater 206, and is installed in the range which is oppositemanifold 209, and may be configured to supply the silicon-containing gasinto the process chamber 201. The nozzle 230 a is connected to the gassupply pipe 232 a. The gas supply pipe 232 a is connected to thesilicon-containing gas source 300 a that supplies the silicon-containinggas, e.g., the disilane gas (Si₂H₆) via the MFC 241 a as a flow ratecontroller (flow rate control member) and the valve 310 a. Thus, thesupply flow rate, concentration, and partial pressure of thesilicon-containing gas, e.g., the disilane gas (Si₂H₆), which issupplied to the process chamber 201 may be controlled. Asilicon-containing gas supply system provided as a gas supply system ismainly configured by the silicon-containing gas source 300 a, the valve310 a, the MFC 241 a, the gas supply pipe 232 a, and the nozzle 230 a.

The nozzle 230 b that supplies a chlorine-containing gas, e.g.,dichlorosilane gas (SiH₂Cl₂) is formed of, for example, a quartzmaterial, and is installed in the manifold 209 to pass through themanifold 209. At least one nozzle 230 b is located below rather than therange which is opposite the heater 206, and is installed in the rangewhich is opposite manifold 209, and may be configured to supply thechlorine-containing gas into the process chamber 201. The nozzle 230 bis connected to the gas supply pipe 232 b. The gas supply pipe 232 b isconnected to the chlorine-containing gas source 300 b that supplies thechlorine-containing gas, e.g., the dichlorosilane gas (SiH₂Cl₂) via theMFC 241 b as a flow rate controller (flow rate control member) and thevalve 310 b. Thus, the supply flow rate, concentration, and partialpressure of the chlorine-containing gas, e.g., the dichlorosilane gas(SiH₂Cl₂), which is supplied into the process chamber 201 may becontrolled. A chlorine-containing gas supply system provided as a gassupply system is mainly configured by the chlorine-containing gas source300 b, the valve 310 b, the MFC 241 b, the gas supply pipe 232 b, andthe nozzle 230 b.

The nozzle 230 c that supplies an inert gas, e.g., nitrogen gas (N₂),may be formed of, for example, a quartz material, and is formed in themanifold 209 to pass through the manifold 209. At least one nozzle 230 cis located below rather than the range which is opposite the heater 206,and is installed in the range which is opposite manifold 209, and may beconfigured to supply the inert gas into the process chamber 201. Thenozzle 230 c is connected to the gas supply pipe 232 c. The gas supplypipe 232 c is connected to the inert gas source 300 c that supplies theinert gas, e.g., the nitrogen gas (N₂) via the MFC 241 c as a flow ratecontroller (flow rate control member) and the valve 310 c. Thus, thesupply flow rate, concentration, and partial pressure of the inert gas,e.g., the nitrogen gas (N₂), which is supplied to the process chamber201 may be controlled. An inert gas supply system provided as a gassupply system is mainly configured by the inert gas source 300 c, thevalve 310 c, the MFC 241 c, the gas supply pipe 232 c, and the nozzle230 c.

The gas flow rate control unit 235 is electrically connected to thevalves 310 a, 310 b, and 310 c and the MFCs 241 a, 241 b, and 241 c soas to control a gas supply amount, start of the gas supply, and end ofthe gas supply at desired timings.

Although, in the present embodiment, the nozzles 230 a, 230 b, and 230 care installed in the range which is opposite 209, the present inventionis not limited thereto. For example, at least some of the nozzles 230 a,230 b, and 230 c may located below rather than the range which isopposite the heater 206 so as to supply the silicon-containing gas, thechlorine-containing gas, or the inert gas to a process region of awafer. For example, at least one L-shaped nozzle may be used, and alocation at which gas is supplied may extend to the process region ofthe wafer in order to supply gas from at least one location to a regionnear the wafer. Furthermore, the nozzles 230 a, 230 b, and 230 c may beinstalled in a region facing either the manifold 209 or the heater 206.

Also, although, in the present embodiment, the disilane gas (Si2H6) isused as the silicon-containing gas, the present invention is not limitedthereto and a high-order silane gas, e.g., silane gas (SiH₄) ortrisilane gas (Si₃H₈), or a combination of such high-degree silane gasesmay be used.

Also, although, in the present embodiment, the dichlorosilane gas(SiH₂Cl₂) is used as the chlorine-containing gas, the present inventionis not limited thereto. For example, a chloro silane-based gas, e.g.,trichlorosilane gas (SiHCl₃) or tetrachlorosilane gas (SiCl₄), chlorinegas (Cl₂) or hydrogen chloride gas (HCl), or a combination thereof maybe used.

Also, although, in the present embodiment, nitrogen gas (N₂) is used asthe inert gas, the present invention is not limited thereto. Forexample, a rare gas, e.g., helium gas (He), neon gas (Ne), or argon gas(Ar), may be used or a combination of nitrogen gas (N₂) and a rare gasmay be used.

In the manifold 209, an exhaust pipe 231 is installed to exhaust anatmosphere in the process chamber 201. The exhaust pipe 231 is disposedat a lower end portion of a tube-shaped space 250 formed by a gapbetween the inner tube 204 and the outer tube 205, and connects to thetube-shaped space 250. A vacuum exhaust device 246, e.g., a vacuum pump,is connected to a downstream side of the exhaust pipe 231 which isopposite to a side of the exhaust pipe 231 connected to the manifold 209via a pressure sensor 245 which senses pressure and a pressure controldevice 242. The vacuum exhaust device 246 is configured to performvacuum-exhaust in such a manner that pressure in the process chamber 201may be equal to a predetermined pressure (predetermined degree ofvacuum). The pressure control device 242 and the pressure sensor 245 areelectrically connected to a pressure control unit 236. The pressurecontrol unit 236 is configured to control the pressure control device242, based on pressure sensed by the pressure sensor 245 at a desiredtiming so that the pressure in the process chamber 201 may be equal to adesired pressure.

A seal cap 219 is installed below the manifold 209 and functions as afurnace port lid configured to air-tightly close a lower end opening ofthe manifold 209. The seal cap 219 is configured to abut a lower end ofthe manifold 209 from a lower side in a vertical direction. The seal cap219 is formed of, for example, stainless steel, and has a disc shape. AnO-ring 220 b which is a seal member that abuts a lower end of themanifold 209 is disposed on an upper surface of the seal cap 219. At aside of the seal cap 219 opposite to the process chamber 201, a rotationmechanism 254 is installed to rotate the boat 217. A rotation shaft 255of the rotation mechanism 254 passes through the seal cap 219 to beconnected to the boat 217 which will be described in detail below. Therotation mechanism 254 is configured to rotate the wafers 200 byrotating the boat 217. The seal cap 219 is configured to be verticallymoved by a boat elevator 115 which is an elevating mechanism verticallyinstalled outside the process tube 203. By vertically moving the sealcap 219, the boat 217 may be loaded into or unloaded from the processchamber 201. The rotation mechanism 254 and the boat elevator 115 areelectrically connected to a driving control unit 237 so as to becontrolled to perform a desired operation at a desired timing.

The boat 217 which is a substrate holder is formed of a heat-resistivematerial, e.g., quartz or silicon carbide, and is configured to hold aplurality of sheets of wafers 200 in the form of a multi-layer structureby arranging the plurality of sheets of wafers 200 horizontally andconcentrically. A plurality of sheets of insulating plates 216 formed ofa heat-resistive material, e.g., quartz or silicon carbide, and havingdisc shapes are each horizontally placed below the boat 217 to form amulti-layer structure. Thus, heat generated from the heater 206 may beprevented from being delivered to the manifold 209.

In the process tube 203, a temperature sensor 263 is installed to sensetemperature. A temperature control unit 238 is electrically connected tothe heater 206 and the temperature sensor 263 so as to control theprocess chamber 201 to have a desired temperature distribution at adesired timing by controlling supply of current to the heater 206, basedon temperature information sensed by the temperature sensor 263.

The gas flow rate control unit 235, the pressure control unit 236, thedriving control unit 237, and the temperature control unit 238 form amanipulation unit and an input/output (I/O) unit, and are electricallyconnected to a main control unit 239 that controls overall operations ofthe substrate processing apparatus. The gas flow rate control unit 235,the pressure control unit 236, the driving control unit 237, thetemperature control unit 238, and the main control unit 239 form acontroller 240.

Next, a method of forming a silicon film on a wafer 200 by chemicalvapor deposition (CVD) using the processing furnace 202 described above,which is a process included in a method of manufacturing a semiconductordevice, will be described below. In the description below, operations ofthe elements of the substrate processing apparatus are controlled by thecontroller 240.

When several sheets of wafers 200 are loaded into the boat 217 (wafercharging), the boat 217 holding the several sheets of wafers 200 islifted by the boat elevator 115 to be loaded into the process chamber201 (boat loading) as illustrated in FIG. 2. In this state, the seal cap219 seals the lower end of the manifold 209 via the O-ring 220 b.

The inside of the process chamber 201 is vacuum-exhausted to a desireddegree of pressure (degree of vacuum) by the vacuum exhaust device 246.In this case, pressure in the process chamber 201 is measured by thepressure sensor 245, and is feedback-controlled by the pressure controldevice 242, based on the measured pressure. The process chamber 201 isheated by the heater 206 so that the inside of the process chamber 201has a desired temperature. In this case, a flow of current supplied tothe heater 206 is feedback-controlled based on the temperatureinformation sensed by the temperature sensor 263, so that the inside ofthe process chamber 201 may have a desired temperature distribution.Then, the wafers 200 are rotated by rotating the boat 217 by therotation mechanism 254.

Then, as illustrated in FIG. 2, for example, a silicon-containing gas issupplied as process gas from the silicon-containing gas source 300 a.The silicon-containing gas, the flow rate of which is controlled to adesired level by the MFC 241 a is introduced into the process chamber201 through the gas supply pipe 232 a and the nozzle 230 a. Then, theintroduced silicon-containing gas moves upward in the process chamber201, is discharged into the cylindrical space 250 through an upper endopening of the inner tube 204, and is then exhausted via the exhaustpipe 231. The silicon-containing gas contacts the surface of the wafer200 when the silicon-containing gas passes through the process chamber201. In this case, a film, e.g., a silicon film, is deposited on thewafers 200 by a thermal CVD reaction.

After a predetermined time has elapsed, an inert gas, the flow rate ofwhich is controlled to a desired level by the MFC 241 c, is suppliedfrom the inert gas source 300 c to replace the atmosphere in the processchamber 201 with the inert gas, thereby allowing the pressure in theprocess chamber 201 to return to a normal pressure.

Then, the seal cap 219 is moved downward by the boat elevator 115 toopen the lower end of the manifold 209, and the processed wafer 200 isunloaded from the lower end of the manifold 209 to the outside of theprocess tube 203 while being held by the boat 217 (boat unloading).Then, the processed wafer 200 is discharged from the boat 217 (waferdischarging).

Next, a method of forming a film according to the first embodiment ofthe present invention will be described in greater detail. By using thesemiconductor manufacturing apparatus 10 described above, a desired filmis formed on a substrate as described below according to a processincluded in a method of manufacturing a semiconductor device.

FIGS. 4A to 4D are diagrams illustrating a state of a substrateaccording to each process in the first embodiment of the presentinvention. As illustrated in FIGS. 4A to 4D, according to the firstembodiment of the present invention, a chlorine-containing gas and asilicon-containing gas are supplied onto a wafer 200 which is asubstrate to form a silicon film having a predetermined thicknessthereon. Thus, the silicon film having the predetermined thickness maybe formed by controlling a thickness distribution in a plane of thesilicon film formed on the wafer 200, as will be described in detailbelow.

First, each process will be described in detail below.

<Nucleus Growth Suppression Process>

This process is performed to suppress local growth of nuclei (impuritiesgenerated on a substrate in an initial stage, formed silicon nuclei,etc.) by partially removing the nuclei or suppressing the growth of thenuclei. As described above, while silicon nuclei are formed on the wafer200, the growth of the silicon nuclei is suppressed by supplying thechlorine-containing gas for a predetermined time, suppressing the growthof the formed silicon nuclei illustrated in FIG. 4A and separating somesilicon nuclei from the wafer 200, as illustrated in FIG. 4B.

Although, in the present embodiment, dichlorosilane (SiH₂Cl₂) gas isused as the chlorine-containing gas, the present invention is notlimited thereto. For example, trichlorosilane gas (SiHCl₃),tetrachlorosilane gas (SiCl₄), chlorine gas (Cl₂), hydrogen chloride gas(HCl), or a combination thereof may be used.

As an example, in the present embodiment, conditions of processing thewafer 200 in the process chamber 201, i.e., conditions of suppressingthe growth of the silicon nuclei on the wafer 200 using thedichlorosilane (SiH₂Cl₂) gas, may include the following:

Process temperature: equal to or greater than 300° C. and is less thanor equal to 500° C.,

Process pressure: equal to or greater than 10 Pa and is less than orequal to 1,330 Pa, and

Supply flow rate of the dichlorosilane (SiH₂Cl₂) gas: equal to orgreater than 10 sccm and is less than or equal to 5,000 sccm,

By maintaining the above conditions to fall constantly within the rangesdescribed above, the growth of the silicon nuclei on the wafer 200 maybe suppressed.

<Nucleus Formation Process>

This operation is performed to form silicon nuclei on the wafer 200which is the substrate. The silicon nuclei can be formed on the entirewafer 200 by repeatedly performing one cycle including the nucleusgrowth suppression process and the nucleus formation process twice ormore. A process of forming a film, e.g., an amorphous silicon film, onthe wafer 200 formed of silicon will now be described. As illustrated inFIG. 4A, at least silicon-containing gas is supplied into the processchamber 201 for a predetermined time so as to form silicon nuclei on thewafer 200.

Silane gas (SiH₄), disilane gas (Si₂H₆), or a combination thereof may beused as the silicon-containing gas.

As an example, in the present embodiment, conditions of processing thewafer 200 in the process chamber 201, i.e., conditions of forming thesilicon nuclei on the wafer 200 using the disilane gas (Si₂H₆), mayinclude the following:

Process temperature: equal to or greater than 300° C. and is less thanor equal to 500° C.,

Process pressure: equal to or greater than 10 Pa and is less than orequal to 1,330 Pa, and

Supply flow rate of the disilane gas (Si₂H₆): equal to or greater than10 sccm and is less than or equal to 5,000 sccm

By maintaining the above conditions to fall constantly within the rangesdescribed above, the silicon nuclei may be formed on the wafer 200.

After the nucleus growth suppression process is performed, the nucleusformation process is performed to form the silicon nuclei on the wafer200, thereby forming new silicon nuclei as illustrated in FIG. 4C. Byrepeatedly performing one cycle including the nucleus growth suppressionprocess (see FIG. 4B) and the nucleus formation process (see FIG. 4C)twice or more, silicon nuclei are evenly formed on the wafer 200 asillustrated in FIG. 4D. Then, a silicon film is formed on the wafer 200by growing the formed silicon nuclei.

Here, a mechanism of controlling the growth of the silicon nuclei willbe described.

The silicon nuclei formed on the wafer 200 may be coarsened to grow asthe silicon film by further supplying the silicon-containing gas.However, when the silicon nuclei are coarsened to grow as the siliconfilm, although the growth of the formed silicon nuclei is promoted,silicon nuclei are formed late on portions of the wafer 200 at which nosilicon nuclei are present. Thus, the sizes of the silicon nuclei formedon the wafer 200 may not be the same. In this case, the silicon filmformed on the wafer 200 has an uneven thickness distribution.

Accordingly, according to the present embodiment, as described above,first, the silicon-containing gas is first supplied once for apredetermined time, and then, the chlorine-containing gas is supplied todelay the coarsening of the silicon nuclei formed on the wafer 200 whenthe silicon-containing gas was supplied once. Then, thesilicon-containing gas is supplied for a predetermined time so as toform silicon nuclei on portions of the wafer 200 on which no siliconnuclei were formed when the silicon-containing gas was first supplied.That is, the sizes of silicon nuclei can be uniformized by forming newsilicon nuclei while suppressing the growth of silicon nuclei that arefirst formed.

As described above, silicon nucleus growth suppression and siliconnucleus formation may be repeatedly performed to evenly form siliconnuclei on the wafer 200. Also, the thickness distribution of the formedsilicon film on the wafer 200 may be improved by controlling the growthof the evenly formed silicon nuclei.

An oxide silicon film may be formed on the wafer 200, and an amorphoussilicon film may be formed on the oxide silicon film as described above.Thus, since an adhesive strength between the amorphous silicon film andthe oxide silicon film is high, it is possible to prevent theperformance of a semiconductor device from being degraded and thethroughput from being lowered.

Also, preprocessing may be performed before the nucleus formationprocess is performed. Thus, impurities adhered onto the wafer 200 may beremoved to form the silicon film without causing the growth of thesilicon nuclei to be interfered with by the impurities.

Also, the atmosphere in a reaction furnace may be replaced with vacuumor nitrogen gas (N₂) by supplying the nitrogen gas between the nucleusgrowth suppression process and the nucleus formation process. Thus, itis possible to efficiently react gases supplied during the processes.

Although formation of a film by CVD has been described above, thepresent invention is not limited thereto, and for example, atomic layerdeposition (ALD) may be used.

After a series of processes are completed, the supply of such processgases is suspended, and inert gas is supplied from an inert gas sourceto replace the atmosphere in the process chamber 201 with the inert gas,thereby returning the pressure in the process chamber 201 to a normalpressure.

Then, the seal cap 219 is moved downward by a lifting motor 122 to openthe lower end of the manifold 209, the boat 217 holding the processedwafer 200 is unloaded from the lower end of the manifold 209 to theoutside of the process chamber 201 (boat unloading), and the boat 217stands by at a predetermined location until all wafers 200 supported inthe boat 217 are cooled. When the stand-by wafers 200 in the boat 217are cooled to a predetermined temperature, the wafers 200 are unloadedfrom the boat 218 by the substrate transfer unit 28, and transferred toand received in the pod 16 that is unoccupied and set in the pod opener24. Then, the pod 16 receiving the wafers 200 is transferred to the podshelf 22 or the pod stage 18 by the pod conveying device 20, therebycompleting the operations of the semiconductor manufacture apparatus 10.

A result of forming a film as described above will now be described.FIG. 5 is a graph showing a result of forming a silicon film asdescribed above. Sample data in the graph of FIG. 5 shows results when atime required to form nuclei was X [sec.] and when times required tosuppress the growth of the nuclei were 0.4X, X, and 2X [sec.]. In thegraph of FIG. 5, the right vertical axis denotes a thickness [Å] of asilicon film formed on a wafer according to each of conditions, the leftvertical axis denotes a variation in thickness distribution [Å] of thesilicon film on the wafer, and the horizontal axis denotes a ratio [−]between a time required for nucleus formation suppression and a timerequired for nucleus formation. The variation in the thicknessdistribution [Å] denotes the difference between a maximum thickness anda minimum thickness of the silicon film on the wafer. When the variationin the thickness distribution [Å] is small, it means that the formedsilicon film is evenly formed on the wafer.

Referring to FIG. 5, as a time required to perform nucleus growthsuppression was relatively longer than a time required to performnucleus formation, i.e., as the ratio [−] between the time required fornucleus formation suppression and the time required for nucleusformation approached zero, the speed of forming a film graduallydecreased. Also, as the time required to perform nucleus growthsuppression became longer than that required to perform nucleusformation (when the ratio [−] between the time required for nucleusformation suppression and the time required for nucleus formationexceeded ‘1.0’), the variation in the thickness distribution [Å]gradually increased. Thus, if this ratio [−] is equal to or greater than‘0.4’ and is less than or equal to ‘1’, a silicon film having a lessvariation in the thickness distribution [Å] may be formed.

According to the present embodiment, at least one or more of thefollowing advantages may be achieved:

(1) A silicon film having an improved thickness distribution can beformed.

(2) An insulating film of silicon can be evenly formed, particularly,when (1) is applied to a semiconductor manufacture process.

(3) In relation to (1), a time required for nucleus growth suppressionmay be between 0.4 and 1 times a time required for nucleus formation.

(4) Good step coverage can be achieved particularly when (1) is appliedto a trench structure having a high aspect ratio or the like.

(5) A semiconductor device having high performance can be stablymanufactured, thereby improving the throughput.

Second Embodiment

Next, a second embodiment of the present invention will be described.The second embodiment is a modified example of the first embodiment ofthe present invention, in which nucleus formation is performed to form afilm after repeatedly performing one cycle including a nucleus growthsuppression process and a nucleus formation process twice or more, aswill be described in detail below.

Each of the processes will now be described in detail.

<Nucleus Growth Suppression Process>

As described above, while silicon nuclei are formed on the wafer 200,the growth of the formed silicon nuclei is controlled by supplying achlorine-containing gas for a predetermined time.

Although, in the present embodiment, dichlorosilane gas (SiH₂Cl₂) isused as the chlorine-containing gas, the present invention is notlimited thereto. For example, trichlorosilane gas (SiHCl₃),tetrachlorosilane gas (SiCl₄), chlorine gas (Cl₂), hydrogen chloride gas(HCl), or a combination thereof may be used.

As an example, in the present embodiment, conditions of processing thewafer 200 in the process chamber 201, i.e., conditions of suppressingthe growth of the silicon nuclei on the wafer 200 using thedichlorosilane gas (SiH₂Cl₂), may include the following:

Process temperature: equal to or greater than 300° C. and is less thanor equal to 500° C.,

Process pressure: equal to or greater than 10 Pa and is less than orequal to 1,330 Pa, and

Supply flow rate of the dichlorosilane gas (SiH₂Cl₂): equal to orgreater than 10 sccm and is less than or equal to 5,000 sccm

By maintaining the above conditions to fall constantly within the rangesdescribed above, the growth of the silicon nuclei on the wafer 200 maybe suppressed.

<Nucleus Formation Process>

A process of forming a film, e.g., an amorphous silicon film, on thewafer 200 which is a substrate formed of silicon will now be described.In this process, silicon nuclei are formed on the wafer 200 by supplyingat least silicon-containing gas into the process chamber 201.

Silane gas (SiH₄), disilane gas (Si₂H₆), or a combination thereof may beused as the silicon-containing gas.

As an example, in the present embodiment, conditions of processing thewafer 200 in the process chamber 201, i.e., conditions of formingsilicon nuclei on the wafer 200 using the disilane gas (Si₂H₆), mayinclude the following:

Process temperature: equal to or greater than 300° C. and is less thanor equal to 500° C.,

Process pressure: equal to or greater than 10 Pa and is less than orequal to 1,330 Pa, and

Supply flow rate of the disilane gas (Si₂H₆): equal to or greater than10 sccm and is less than or equal to 5,000 sccm

By maintaining the above conditions to fall constantly within the rangesdescribed above, the silicon nuclei may be formed on the wafer 200.

<Nucleus Growth Process>

This process is performed to grow the silicon nuclei formed on theentire wafer 200 after one cycle including the nucleus growthsuppression process and the nucleus formation process is performed twiceor more. As described above, while the silicon nuclei are evenly formedon the wafer 200, a silicon film is formed by supplying asilicon-containing gas for a predetermined time to grow the formedsilicon nuclei.

Silane gas (SiH₄), disilane gas (Si₂H₆), or a combination thereof may beused as the silicon-containing gas.

As an example, in the present embodiment, conditions of processing thewafer 200 in the process chamber 201, i.e., conditions of controllingthe growth of the silicon nuclei on the wafer 200 by using the silanegas (SiH₄), may include the following:

Process temperature: equal to or greater than 300° C. and is less thanor equal to 500° C.,

Process pressure: equal to or greater than 10 Pa and is less than orequal to 1,330 Pa, and

Supply flow rate of the silane gas (SiH₄): equal to or greater than 10sccm and is less than or equal to 5,000 sccm

By maintaining the above conditions to fall constantly within the rangesdescribed above, the silicon nuclei formed on the wafer 200 may be grownto become a silicon film.

Accordingly, the silicon film may be formed by efficiently growing thesilicon nuclei evenly formed on the wafer 200.

According to the present embodiment, at least one of the followingadvantages may be further achieved, in addition to the advantages thatmay be achieved according to the first embodiment.

(1) A silicon film can be formed by efficiently growing the siliconnuclei.

(2) In relation to (1), consumption of a source gas can be reduced.

The present invention may be applied not only to batch-type apparatusesbut also to single-type apparatuses.

Also, the preset invention has been described above with respect toformation of a polysilicon film, but may also be applied to formation ofan epitaxial film or a CVD film, e.g., a silicon nitride film.

According to the present invention, degradation in the quality of asubstrate or the performance of a semiconductor device can be prevented.

What is claimed is:
 1. A method of manufacturing a semiconductor device,comprising forming a silicon film by performing a cycle at least twice,the cycle including a nucleus growth suppression process of supplying achlorine-containing gas onto a substrate to suppress a growth of nucleiand control a local growth of silicon on the substrate and a nucleusformation process of supplying a silicon-containing gas onto thesubstrate to form silicon nuclei on the substrate, wherein a timerequired for the nucleus growth suppression process is less than orequal to a time required for the nucleus formation process.
 2. Asubstrate processing apparatus comprising: a process chamber configuredto process a substrate; a chlorine-containing gas supply systemconfigured to supply at least a chlorine-containing gas into the processchamber; a silicon-containing gas supply system configured to supply atleast a silicon-containing gas into the process chamber; and acontroller configured to control at least the chlorine-containing gassupply system and the silicon-containing gas supply system to form asilicon film by performing a cycle at least twice, the cycle including anucleus growth suppression process of supplying the chlorine-containinggas onto the substrate to suppress a growth of nuclei and control alocal growth of silicon on the substrate and a nucleus formation processof supplying the silicon-containing gas onto the substrate to formsilicon nuclei on the substrate, wherein a time required for the nucleusgrowth suppression process is less than or equal to a time required forthe nucleus formation process.
 3. The method of claim 1, furthercomprising performing the nucleus formation process after the cycle isperformed at least twice.
 4. The method of claim 1, wherein the timerequired for the nucleus growth suppression process is 0.4 to 1 timesthe time required for the nucleus formation process.